Apparatus for producing expanded metal



Aug- 30, 1966 M1. FELSENTHM, 3,26%,973

APPARATUS FOR PRODUCING EXPANDED METAL Original Filed April 24, 1962 2Sheets-Sheet l /0 m H6., m H6.

Aug. 30, 1966 R. M. FELSENTHAL. 3,263,973

APPARATUS FR PRODUCING EXPANDED METAL Original Filed April 24, 1962 2Sheets-Sheet 2:

United States Patent O 3,268,973 APPARATUS FR PRDUCING EXPANDED METALRobert M. Felsenthal, Westport, Conn., assiguor to Exmet Corporation,Bridgeport, Conn., a corporation of Delaware @riginal application Apr.24, 1962, Ser. No. 189,839, now Patent No. 3,162,925, dated Dec. 29,1964. Divided and this application Nov. 16, 1964, Ser. No. 411,412 1Claim. (Cl. 29-6.2)

This invention relates generally to metallic sheet material commonlyknown as expanded metal, in which successive staggered rows of lpendantsheared strands are linked together by connecting bridges, and 'hasparticular reference to improved apparatus for making such material.Coordinately, the invention relates to the improved products therebycreated.

This application is a division of my copending application, Serial No.189,839, filed April 24, 1962 `(now Patent No. 3,162,925 issued December29, 1964).

4It is a general object of the invention to remedy one of theshortcomings of the commonly employed manufacturing procedure in which ashear plate and a serrated punch are reciprocated in shearing relationto each other and laterally shifted between she-aring operations, whilethe sheet to be treated is advanced stepwise to subject successive areasto -the shearing action of the punch. An almost inevitable result ofthis method of procedure is the creation of expanded metal in which theconnecting bridges between the strands are of angled character. This isespecially manifest in cases involving melatively ductile metals or inwhich the strands are relatively wide in comparison to the thickness ofthe 4original sheet. The angling referred to is in the lengthwisedirection of the sheet `and resides in the disposition of the forwardhalf of each connecting bridge in a plane at an angle to the rearwardhalf. This structural condition has certain disadvantages,

. and `it is a specific object of this invention to overcome this. Afurther object is to attain the added advantages of an expanded met-alin which the connecting bridges are relatively straight and lie insubstantially single planes.

It is a well-known characteristic of expanded metal, manufactured asdescribed, that the connecting bridges lie at an oblique angle to theplane of the nished product. By avoiding the buckling or anglingmentioned above, and by causing each bridge to remain in 'asubstantially single plane, improved characteristics can be imparted tothe product, depending upon the use for which it is intended. Forexample, the product can be caused to have greater over-all thickness,increased stiffness, or greater crushing resistance. Also, the free ilowof fluids through the mesh can be enhanced. These are illustrative ofthe benefits resulting from the present invention.

Some of these advantages have been sought to be achieved, heretofore, byspecial stretching or distortion of the mesh longitudinally, after itsinitial formation, and by procedures combing slitting and stretching inclosely related sequences. The present invention achieves the desiredobjects without necessitating any additional stretching operations.Moreover, it is applicable to met-als and alloys of -specializedcharacter, :and useful in mesh sizes and shapes for which apparatus andprocedures hereto-fore employed have been unsuitable.

It is -a further object of the invention to achieve all these desirableresults by apparatus of relatively simple character, thoroughlypractical and inexpensive from a manufacturing standpoint, and reliableand effective in use.

Several ways of achieving these objectives, and such other object and`advantages as may hereinafter be pointed ice out, are shown by way ofexample in the accompanying drawings, in which:

.FIG 1 is a fragmentary elevational View, of simplified diagrammaticcharacter, of a conventional shear plate and punch at the commencementof .a sequence of operations resulting in the formation of expandedmetal;

FIGS. 2-5 are similar views of successive operations;

FIG. `6 is a cross-sectional -view substantially along the line 6h-6 ofFIG. 4;

FIG. 7 is a View similar to FIG. 6 showing a sub sequent step in theprocess;

FIG. 8 is a cross-sectional view substantially along the line 8-a8 ofFIG. 5;

FIG. 9 is a face view of a piece of the resultant expanded metal;

FIG. `l0 is an enlarged fragmentary cross-section along the line lll-10of FIG. 9;

FIG. 11 is a view similar to FIG. 10, showing by comparison Ithe nat-ureof the improved result achieved by the present invention;

FIG. 12 is a view similar to FIG. 1, showing one form of the improvedapparatus;

FIG. 13 is a cross-sectional view substantially along the line 13-13- ofFIG. 12;

IF-IG. 14 is a view similar to FIG. l2, showing one embodiment of thecorrelating mechanism;

FIG. 15 is a view similar to FIG. l2, showing a second embodiment of thecorrelating mechanism;

FIG. 16 is a View similar to F-IG. 12, showing an alternative apparatusand procedure;

. FIG. 17 is an exaggerated longitudinal cross-section of an expandedmetal product resulting from this invention; and

FIG. 18 is an illustrative mechanism for intermittently advancing asheet t-o be treated.

FIGS. l-10 depict known apparatus of the guillotine type, and show in anexaggerated manner the shortcomings which the present invention hasovercome.

A shear blade or plate 20 and a punch 21 are arranged in shearingrelationship. A sheet of metal to be treated (22) is advancedintermittently (in the direction of the observer in FIGS. l-5) to bringsuccessive regions into an overhanging relation to the shear plate 20and thus subject them to the shearing action of the punch 21. (Theintermittent advance of the sheet 22 may be brought about by anyconventional means, e.g., by a mechanism (FIG. 18) in which one of twofeed rollers 80' carries a ratchet 81 actuated by a pawl 82, reversemovement being prevented by a spring-pressed pivoted keeper 83. Pawl 82is pivoted at 84 to an arm 85 that rocks on -axis 86 and is pivoted at87 to an actuating link 88 connected at 89 to a drive wheel 90 driven bythe main shaft of the machine.) These advancements of the metal 22 occurduring the periods that the punch 21 is withdrawn from the shear plate(FIGS. l, 3, 5). During these periods there is also a relative lateralshift of punch 21 and sheet 22.

The punch 121 is serrated, i.e., it has tooth-like parts 23 withintervening recesses or depressions 24. These can be shaped or contouredin various ways to produce correspondingly different effects. The endsof the teeth 23 are preferably blunted, 'as shown.

Assuming in FIG. 1 that the sheet 22 is in a position in Iwhich itsadvancing margin overhangs the edge of the shear plate 20 by the desiredamount, the punch 21 is now caused to descend to the position of maximumadvance shown in FIG. 2. This shears the pendant strands 25, whichnevertheless remain Connected to the parent sheet in the regions 26between the serrations 23` of the punch 21. The punch then withdraws andshifts laterally relative to sheet 22, as indicated by arrows in FIG. 3.During this period, the sheet 22 advances again to bring the nextsuccessive region into shearing position. On the next descent of thepunch 21 (FIG. 4) the serrations encounter the regions 26 and shear thenext row of pendant strands 27. These are similarly retained inconnected relation to the parent sheet in the regions 28 between theserrations 23 of the punch. Again, the punch 21 withdraws (FIG. andshifts back to the position of FIG. 1, while the sheet 22 advancesagain. This sequence of steps is repeated again and again, as often asmay be desired. The resultant product is shown in FIG. 9, there beingsuccessive staggered rows of pendant sheared strands linked together byconnecting |bridges. In FIG. 9, the two rows at the bottom are numberedto correspond to the procedural steps described in connection with FIGS.1-8.

One of the connecting bridges is shown on an enlarged scale in FIG. 10.It will be noted that its forward half 29 has 'been angled out of theplane of the rearward half 30. This is due to the pulling action of thepunch 21 during each shearing operation. As indicated in FIGS. 6 and 7,the rearward part of each connecting bridge remains in a plane parallelto the original plane of the sheet 22, but during the shearing operationthe forward halves of the next set of connecting bridges, which are thenin positions overhanging the shear plate 20, are pulled downwardly. Thesuccessive angulations are shown in a somewhat exaggerated manner inFIGS. 6, 7, 8 and 10, for the sake of clarity.

The degree to which the bridges will distort as described depends uponnumerous factors. For example, it varies with the mesh length (i.e., thepitch of the teeth on the serrated punch). It also varies with the depthto which the punch descends during the shearing procedure, with thenature and thickness of the sheet being treated, and with the ratio ofstrand width (W) to sheet thickness (T) as indicated in FIG. 10.Usually, if the ratio W/ T is greater than 2 (and often it may be ashigh as 5) the distortion of the connecting bridges attains appreciablemagnitude.

In contrast to this, the expanded metal produced by the presentinvention (using the same sheet material, sheet thickness, and W/ Tratio) has a cross-sectional conguration of the nature indicated in FIG.11. The forward half of each bridge lies in substantially the same planeas the rearward half. This result is achieved by providing a specialmeans for supporting the overhanging areas of the sheet, during eachshearing operation, in the regions between the serrations of the punch.

In the embodiments of the invention shown in FIGS. 12-16, the supportmeans is a comb-like element directly adj-acent to the shear plate anddirectly beneath the overhanging sheet area, the comb being providedwith serrations or teeth-like parts facing toward and in complementaryalignment with those of the punch. In FIGS. 12 and 13, for example, acomb 32 of this character is secured at -against the outer face of theshear plate 33, directly adjacent to the shearing edge. The element 32has teeth 34 and intervening depressions 35, corresponding in size andspacing to the teeth 36 and depressions 37 of the punch 38. The Ibluntedends of teeth 34 lie substantially at the level of the shearing edge ofplate 33. As a result, when the punch 38 descends to the position shownin dot-and-dash lines, the sheet 39 is correspondingly sheared ashereinbefore described, but the overhanging regions 40 between theserrations 36 of the punch are supported from beneath by the serrations34 of the comb 32. This etfectively counteracts the tendency of thepunch 38 to pull these regions 40 out of the plane of the sheet 39, andthus the connecting bridges of the resultant product are straight andunbent as shown in FIG. 1l. l

It is necessary, of course, to correlate the relative movements of theshearing parts and the sheet itself so that a supporting comb or itsequivalent is always in position to exert the desired supportingfunction upon the con- 4 necting bridges that are being formed. Thereare several ways of doing this, and they are illustrated in FIGS. 14-16inclusive.

In FIG. 14, the supporting comb 41 is mounted in laterally shiftablemanner with respect to the shearing plate 42. This shiftability isindicated by the arrows 43. At its ends the comb 41 carries guide posts44. The punch 45 is provided with ears or projections 46 having guideholes through which the posts 44 extend. In this Way to punch 45 is ableto reciprocate up and down (arrows 4'7) relative to the shear plate 42and support comb 41, whereas both the punch 4S and the comb 41 arelaterally shiftable in unison.

The means for moving the punch toward and away from the shear plate, andalso laterally back and forth, and the means for intermittentlyadvancing the sheet being treated, have not been shown in detail in anyof the figures. Any known motive power or mechanisms, properly actuatedin timed relation, can be employed for these purpose. Guiding means suchas guide rails or the like, and other structural elements and expedientsof commonly known character, have also been omitted from the drawingsfor the sake of simplicity.

It will be understood that the treatment of a sheet of metal by theapparatus shown in FIG. 14 will be carried out in the mannerhereinbefore described. The sheet has not been illustrated, but it isadvanced intermittently along the top face of the shear plate 42 tobring successive areas into an overhanging relationship and into therange of action of the shearing punch 45. During each period ofwithdrawal of the punch 45 the sheet to be treated is advanced, whilethe punch 45 (and with it the comb 41) is shifted laterally, eg., bypushrods 14S or the like. In this way there is always a prop or supportunder each overhanging area lying between the serrations of the punch.

In FIG. l5, an arrangement is shown in which the punch 48 has ears 49provided with vertical slots 50. Riding in each slot is a pivot pin 51carried at the upper end of a connecting link 52. The link 52 is pivotedto a fixed central axis 53 mounted on a stationary part of theapparatus. At its lower end, the link 52 is pivoted as at 54 to thesupporting comb 55, guided in any suitable way for lateral reciprocationas indicated by arrows 56. The slots 50 allow the punch 48 to move upand down in shearing relation to the shear plate 57, and the links 52serve to interengage the punch 48 and the comb 55 so that the requiredcomplementary alignment is automatically established during each cycleof operation. Unlike the arrangement of FIG. 14, the punch 48 and thecomb 55 move laterally in opposite directions, and the extent ofmovement of each is half the pitch of the serrations. Thus, whereas thetooth 58 of the comb 55 is shown in FIG. 15 in alignment with the recessor depression 59 of the punch 48, the recess 59 will become aligned withthe tooth 60 of the comb after the parts have shifted laterally asindicated by the dot-and-dash position of the link 52. As a result, uponeach descent of the punch 48 into shearmg relationship to the shearplate 57, there is a prop or support under the overhanging areas of thesheet lying between the serrations of the punch. As in the case of FIG.14, the sheet to be treated has not been shown in FIG. l5, but the modeof procedure will be readily understood from the descriptionhereinbefore given.

FIG. 16 shows the possibility of leaving the punch 61 and the supportingcomb 62 laterally fixed at all times (although the punch is movable upand down as indicated at 63), and achieving the desired objective byshifting the sheet 64 laterally back and forth as indicated by thearrows 65 and the pushers 66. Of course the entire shear plate 67 mightbe caused to participate in this lateral reciprocation, if desired,provided that relative movement of the shear plate 67 with respect tothe fixed comb 62 is pro-v vided for.

In FIG. 17 some of the advantages of the improved expanded metal areillustrated diagrammatically. The overall thickness of the improvedproduct is indicated at 77.

In contrast to this, because of the angling of each of the connectingbridges, as indicated in dot-and-dash lines, the overall thickness ofthe conventional expanded metal product, formed of the same originalsheet, would be as indicated at 76. Coupled with this increased overallthickness is added rigidity, greater strength, and wider passagesthrough the mesh. Wider passages allow flow or accommodation of morefluid, paste, or ne powder than would be afforded by narrower passages.

It will be understood that many of the details herein described andillustrated may be modified by those skilled in the art withoutnecessarily departing from the spirit and scope of the invention asexpressed in the appended claims,

What is claimed is:

In apparatus for producing an expanded metal sheet in which successivestaggered rows of pendant sheared-out strands are linked together byconnecting bridges:

(a) a shear plate and a serrated punch reciprocable in shearing relationto each other,

(b) means for causing stepwise advancement of the sheet to be treated,to bring successive areas into overhanging relation to the shear plateand thus subject them to the shearing action of said punch,

(c) means for effecting a relative back-and-forth lateral shift of punchand sheet between shearing operations, said means comprising means forimparting lateral back-and-forth movements to the sheet while the punchremains laterally stationary, and

(d) means for supporting the overhanging area of the sheet during eachshearing operation in the regions between the serrations of the punch soas to counteract the tendency of the punch to pull 'the connectingbridges out of the plane of the sheet,

said means comprising a laterally stationary comb directly adjacent toand in contact. with the shear plate and directly beneath theoverhanging sheet area, said comb having serrations facing toward and incomplementary alignment with those of the punch, the peak of each combserration lying substantially at the level of the shearing edge of saidplate.

No references cited.

RICHARD H. EANES, JR., Primary Examiner.

